A saw machine generally has safety devices to protect users from accidental injuries. For example, a riving knife is typically fixedly mounted at the machine base behind the saw blade to provide protection against cutting and kickback accidents. Further, a saw blade guard can be pivotally mounted at the top side of the riving knife. Such a saw blade guard can extend over the top side of the saw blade to guard the saw blade from accidental contact with an operator.
In order to meet international safety codes, the processes of mounting and maintaining the accessories of a saw machine have become much more complicated. To meet maintenance and mounting requirements for the aforesaid safety devices for a saw machine, these safety devices are all designed to be detachable. Thus, quick release structures for quick mounting and dismounting of safety devices have become the standard for a saw machine.
U.S. patent application Ser. No. 2008/0223189A1 discloses a quick release structure for a saw machine, which includes a curved guide groove located on the top side of a saw blade guard, and a control device. The control device includes a first engagement wheel, a link, and a third engagement wheel pivotally connected to the rear end of the link and guided by the guide groove. Further, a retaining notch is located on the top edge of a riving knife. In order to mount the saw blade guard to the riving knife, the first engagement wheel is attached to one side of the retaining notch, and then the control device is operated. By means of the linking operation of the link, the third engagement wheel is guided by the guide groove into engagement with the other side of the retaining notch to lock the saw blade guard to the top side of the riving knife. This quick release structure enables the saw blade guard to be quickly locked to and unlocked from the riving knife. However, the whole structure comprises a large number of component parts, so assembly of the quick release structure is cumbersome. Furthermore, because the guide groove is curved, the movement of the third engagement wheel along the curved guide groove is unsmooth and requires increased effort.